| In China,public private partnership(PPP)is being used or planned to implement rail transit project construction.However,rail transit PPP projects have many risk factors,which can significantly affect the overall performance of PPP projects.On the one hand,the existing research lacks systematic identification and evaluation of risk factors of rail transit PPP projects.On the other hand,most studies adopt importance ranking methods to evaluate risks,ignoring the interactions among risks.To fill up this research gap,this study identifies 35 risk factors of rail transit PPP projects by historical documents and expert interview.The above risk factors are divided into seven categories: political and legal risk,economic risk,social and natural risk,project implementation stage risk,operation stage risk,transfer stage risk and relational governance risk,which provides a basis for classification management.Social network is an effective tool to analyze risk interactions,but the existing risk assessment model of social network has deviation in revealing the topological nature of risk network.In order to evaluate the interactions of identified risk factors more accurately,this paper improves the existing social network risk assessment model and establishes a weighted network risk assessment model.This study evaluates the degree of risk interactions through questionnaire survey,and explores the comprehensive impact of risk interactions on rail transit PPP project through weighted network risk assessment model.Finally,the risk management strategy of rail transit PPP project is put forward from the two dimensions of risk factor and risk category characteristics.The research findings show that the risk network of rail transit PPP projects has strong interactions,and there are obvious cause–effect relationships among many risk factors.In addition to the direct impacts of risk factors,the indirect impacts between risk groups are also significant.Generally speaking,the occurrence of risk events in rail transit PPP projects is the result of the interactions of risk factors of multiple risk categories.The risk management of rail transit PPP projects should shift from separate risk mitigation to collaborative risk responses. |
